The present invention relates generally to IC cards, and more particularly, to an IC card capable of displaying a response state in a data communication.
There have been known IC cards used for a data communication with an externally provided interrogator.
FIG. 6 is a schematic block diagram of the basic configuration of a conventional IC card 300. The conventional IC card 300 as shown is a signal superposing, non-contacting type IC card, supplies power and transmits/receives information using a signal(s) having one or more frequencies received from an interrogator which is not shown.
IC card 300 shown in FIG. 6, an example of an IC card using a single frequency, includes a tuning circuit 15, a rectifying circuit 16, an amplifying/demodulating circuit 17, a modulating/amplifying circuit 18, and an SP/PS conversion circuit 19.
Tuning circuit 15 includes a coil L functioning as an antenna and a capacitor C. Rectifying circuit 16 rectifies a signal received at tuning circuit 15 to generate electric power and supplies the power to each part of IC card 300. Meanwhile, amplifying/demodulating circuit 17 amplifies and demodulates information Q from an interrogator received at tuning circuit 15. A signal output from amplifying/demodulating circuit 17 is SP-converted by SP/Ps conversion circuit 19.
Referring to FIG. 6, this conventional IC card 300 includes a main control circuit 11 and a memory 10.
Main control circuit 11 processes a signal output from SP/PS conversion circuit 19. Data output from main control circuit 11 which is to be held is stored (held) in memory 10 for holding data.
Main control circuit 11 reads out data from an addressed region of memory 10 based on the content of information Q received from the interrogator, and generates response information A based on the read out data. Response information A is PS-converted by SP/PS conversion circuit 19, then processed by modulating/amplifying circuit 18 and transmitted to the interrogator through antenna L.
The response state of such conventional IC card 300 is verified exclusively on the side of the interrogator which is not shown, in other words, conventional IC card 300 does not have a function to verify the response state.
Therefore, information on what is going on in IC card 300 is not available to the side of the user of the card.
For example, if a plurality of IC cards 300 perform a data communication simultaneously or sequentially without time interval, and a response abnormality from any of IC cards 300 is detected on the side of interrogator, the user cannot find which IC card 300 has the abnormality in the data communication.
Thus, the reliability of the entire system including the interrogator and the responding element (IC card) can be hardly secured.
It is therefore an object of the present invention to provide an IC card permitting the user to recognize a response state in a data communication.
Another object of the invention is to provide an IC card capable of continuously displaying a response state in a data communication for a prescribed time period.
An IC card according to the present invention performs a data communication in response to externally applied data, and includes a control circuit to control data reception and a response, and a display to display a response state in response to an instruction from the control circuit.
An IC card according to another aspect of the invention performs a data communication in response to externally applied data, and includes a storing circuit to which the externally applied data is written, a control circuit to control a response using the data written in the storing circuit, and a display to display a response state in response to an instruction from the control circuit.
An IC card according to a further aspect of the invention performs a data communication in response to externally applied data, and includes a first storing circuit to which the externally received data is written, a second storing circuit to save the written data in the first storing circuit, a control circuit to make control for making a response using data in the first or second storing circuit, and a display circuit to display a response state in response to an instruction received from the control circuit.
Therefore, a main advantage of the present invention resides in that the user may readily visually recognize a response state in a data communication.